PoE system for the distribution of high voltage power

ABSTRACT

The present invention provides a system comprising PoE apparatus including midspans, switches and routers that can provide high powered PoE connections that enable the recovery of DC power in sufficient quantities that allow it to be converted to AC power by way of an inverter. The invention also provides a method for providing AC power, data and light to office workstations using a single PoE connection. The invention further comprises a common mode signaling system that operates independently of any TCP/IP signal transmitted through an Ethernet connection wherein said signaling system is adapted to communicate with and control PoE powered devices.

TECHNICAL FIELD

The present invention relates principally to PoE apparatus together witha communications and signaling system for the distribution of power,data and lighting.

BACKGROUND ART

It will be clearly understood that, if a prior art publication isreferred to herein, this reference does not constitute an admission thatthe publication forms part of the common general knowledge in the art inAustralia or in any other country.

The distribution and provisioning of power, data and lighting servicesin a building represents one of the most important stages in a buildingsconstruction. Further such steps often occur on repeated occasionsthroughout a buildings life, particularly if the building is acommercial building that is “refitted” on a regular basis when newtenants are introduced, or when an existing tenant decides to alter thefloor plan and utilization of a space.

A high proportion of the provisioning of power, data and lightingservices in office fit outs is for the purpose of providing services todesks and workstations where office workers complete their tasks. Insome cases, hundreds of workstations are required to be serviced on eachfloor. In conventional fit outs, each floor of a commercial officebuilding has a distribution board from which a plurality of high voltagecircuits connected to each circuit breaker of the distribution board.These circuits deliver high voltage (240V or 110V AC) for mains powerpoints which are used by the workers at their workstations to powercomputers, monitors, printers etc. The circuits run along cable trays,catenary wire and conduits in the ceiling space or below the surface ofa raised floor. They are connected to general power outlets in theworkspace by way of electrical risers which provide access to below thefloor, via umbilical cords extending down from the ceiling, or via wallsand skirting boards in which general power outlets are located.

In addition to providing 240V AC/110V AC (which will hereafter bereferred to as high voltage power) for general power outlets, highvoltage power is also distributed from the distribution board for thepowering of luminaires for the lighting of the office workspace.

It is a requirement in most countries that electrical work including theinstallation and removal of 240V AC/110V AC circuits and general poweroutlets be conducted by licensed and qualified, electricians. Findinglicensed electricians can often lead to delays during the fit-out stageof construction as they are generally in high demand. Further, by virtueof the work required to redesign and redeploy the electrical circuits,cable trays, conduits, electrical risers, umbilical cords, general poweroutlets and lights when a change of use occurs, such a change canrepresent a huge disruption to the workers and the business. In manycases tenants prefer to move rather than risk the disruption that occursduring the rewiring of a floor of an office building. Even if the workis conducted over a weekend, the changes required, and the costsincurred in performing the works are very substantial and represent lostopportunities associated with the occupancy of the building.

By contrast, the provision of data cabling during office fit outs isless onerous. Firstly, as data cables, principally comprising Ethernetcables, run at extra low voltage (less than 60V DC), the rulessurrounding the treatment of data cables, such as those set out inAS/NZS 3000:2007 and AS/ACIF S009:2013, are much more relaxed. Forinstance, it is not a requirement that data cabling is installed byfully qualified licensed electricians. Further, the cables themselves donot need to be encased in conduit or ducts or maintained on cable traysin the same way as high voltage cables.

In recent years there has been a movement to utilize power over Ethernet(PoE) for the powering of LED lights. However, the current standards ofPoE do not provide sufficient power over the Ethernet connections todrive the plurality of lights necessary as in the case of a commercialoffice fit out. In Australian Innovation Patent Application 2016100103,which is incorporated herein by reference, the applicant disclosed theuse of high powered PoE technologies to power LED lights featuring RJ-45connections. However even accounting for the reduction in high voltagecabling that this innovation brought with it, there remained the issueof the remaining high voltage cabling used to provide general poweroutlets. The continued use of high voltage cabling represents a problemin terms of safety and inflexibility. It is desirous that the use ofhigh voltage cabling in buildings is minimized and more extra lowvoltage cabling is used instead, as it is safer and can be installed orremoved by non-electricians. Further, the applicant in AustralianInnovation Patent Application 2016100103 proposed a complicated andexpensive method of controlling the connected LED lights using a NUCcomputer. It would be preferable to have a simpler and less expensivemethod of communicating and/or controlling connected devices that doesnot rely on high level communication protocols including TCP/IP.

The present invention, therefore, seeks to overcome or substantiallyameliorate the shortcomings of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are provided to illustrate the nature of theinvention in each of its aspects and preferred embodiments, namely:

FIG. 1 is a schematic of the PoE system of the invention according to afirst aspect of the invention.

FIG. 2 is a schematic of a PoE injector and PoE splitter spanned by aPoE connection.

FIG. 3 is a schematic of a PoE power source equipment (PSE) of the PoEsystem.

FIG. 4 is a schematic of a PoE powered distribution unit (PDU) of thePoE system.

FIG. 5 is a schematic of a PoE PSE comprising a midspan with a pluralityof PoE injectors.

FIG. 6 is a schematic of an 8 port PDU of the PoE system.

FIG. 7 is a front view of a desktop single channel PDU.

FIG. 8 is a rear view of a desktop single channel PDU.

FIG. 9 is a side view of a desktop single channel PDU.

FIG. 10 is a front view of an alternate embodiment of a single channelPDU with lighting control functionality for desktop use.

FIG. 11 is a rear view of an alternate embodiment of FIG. 10 .

FIG. 12 is a front view of a single channel PDU for use with luminairesin the ceiling space.

FIG. 13 is a rear view of the ceiling single channel PDU of FIG. 12 .

FIG. 14 is a schematic view of a PSE injector according to a furtherembodiment of the invention which uses an alternative method ofcommon-mode injection of control signaling, using a tapped choke inwhich the signal is injected on the positive supply side.

FIG. 15 is a schematic view of a PSE injector according to a stillfurther embodiment of the invention in which a tapped choke is used toinject signal on the negative supply side.

FIG. 16 is a schematic view of a PSE injector according to a stillfurther embodiment of the invention in which two separate chokes feedeither side of the differential lines and the signal is injected on thepositive supply side.

FIG. 17 is a schematic view of a PSE injector according to a stillfurther embodiment of the invention in which two separate chokes feedeither side of the differential lines and the signal is injected on thenegative supply side.

FIG. 18 is a perspective view of a rack mounted equipment of the PoEsystem.

FIG. 19 is a front view of a modified M12 Ethernet socket.

FIG. 20 is a perspective view of a modified M12 Ethernet socket.

FIG. 21 is a side view of a modified M12 Ethernet socket.

FIG. 22 is a front view of a modified M12 Ethernet jack.

FIG. 23 is a front view of a modified M12 Ethernet jack.

FIG. 24 is a front view of a modified M12 Ethernet jack.

FIG. 25 is a schematic of a 4 port PDU in which the 4 sources of DCpower are arranged in parallel.

FIG. 26 is a schematic of a 4 port PDU in which the 4 sources of DCpower are arranged in series.

FIG. 27 is a schematic of a 4 port PDU in which the 4 sources of DCpower are fed into a multi input inverter.

FIG. 28 is a LED luminaire which is powered by PoE and controlled by wayof common mode signaling delivered over the PoE connection.

FIG. 29 is an emergency lighting LED luminaire which is powered by PoEand controlled by way of common mode signaling delivered over the PoEconnection.

FIG. 30 is a perspective view of a soft-wiring desk module for providingGPO, USB and Ethernet connectivity using software wiring.

FIG. 31 is a perspective view of a soft wring GPO module adjacent to anintegrated USB charging module.

FIG. 32 is a perspective view of the modules of FIG. 31 that have beenconnected.

FIG. 33 is a cross sectional view of a Cat6A shielded cable that hasbeen conjoined to an insulated earthing conductor cable by joining thetwo cables along their lengths.

FIG. 34 is a cross sectional view of a Cat6A cable collocated with aninsulated earthing conductor cable by encasing both cables in a commonsheath.

FIG. 35 is a cross sectional view of a Cat6A shielded cable with anextra insulated earthing conductor which can be used as a ninthconductor for providing an earth.

FIG. 36 is a cross sectional view of a Cat6A shielded cable with 8conductors, wherein the foil shielding can be used as a ninth conductor.

MODES FOR CARRYING OUT THE INVENTION

As set out in the summary of invention, there are two main aspects ofthe invention. The first aspect resides in a number of powerdistribution devices which are capable of delivering high voltage AC towhere it is required in a building by transmitting low voltage DC powerover Ethernet cables then inverting the DC power at the destinationusing a power distribution unit (PDU) which produces high voltage ACpower for use at the destination. As the PDU's can also deliver data inthe form of Gigabit or 10 Gigabit Ethernet connections together with theAC power, the provision of a single Ethernet cable with a minimum of 100W of PoE power would be sufficient to meet the basic needs of officeworkers today.

For example, a typical office worker's power consumption would be as setout in Table 1.

TABLE 1 Device PC (Laptop) Monitor USB Fan VOIP Phone Total Peak 60 W 20W 2.5 W 7 W 89.5 W Average 45 W (with 20 W 2.5 W 7 W 74.5 W 30% charge)

No currently ratified PoE standard is capable of delivering this levelof power over a single PoE connection for reconversion to AC power insufficient quantities to meet the needs of the average office worker.802.3bt Type 4 more commonly known as PoE++ is capable of delivering 71W at the powered device (100 W at the PoE source). PoE++ is not an asyet agreed and ratified standard. It is expected to become ratified inthe coming years.

In Australian Innovation Patent Number 2016100103, which is hereinincorporated by reference, the applicant discloses a number ofnon-standards compliant sources of high power PoE connections for use inpowering RJ-45 equipped LED luminaires. It has been discovered by theapplicant that even higher power PoE connections can be created andutilized provided certain safety measures are taken. These safetymeasures need to be taken as combining multiple high powered, lowvoltage DC PoE connections can result in a great deal of power passingthrough very thin conductors that are found in Ethernet cables. Byvirtue of the nature of the location of these cables in ceilings andunderfloor access ducts, any overheating cables could lead tocatastrophic fires.

In addition to apparatus for providing high voltage AC power bytransmitting low voltage DC power, the present invention incorporates anovel communications and control method and apparatus for implementingthe method. The method utilizes communication through the physical layerof the Ethernet connection and allows devices at both ends of a PoEconnection to send and receive data comprising commands and/or data. Assuch the method is adapted to control the state of PDU devices poweredby and connected to the PoE connection from the power source equipment(PSE). It is also adapted to receive data from PDUs that have beenequipped with sensors such as temperature or light sensors.

The embodiments of the first aspect of the invention have been describedtogether with the third aspect of the invention (comprising the fourthaspect of the invention). It should be noted however, that the applicantcontends that each aspect is in itself novel and inventive and are theproper subject of the grant of letters patent. Accordingly, whilst thePSE and PDU devices of the present invention have been described withmicrocontrollers and suitably adapted injectors and splitters thatfacilitate communication across the physical layer of the Ethernetconnection they are nonetheless useful without the communicationscapability.

Referring to FIG. 1 there is an overview of the PoE system 10. The PoEsystem 10 is comprised of PSE devices 12 which are a source of highpowered PoE connections. The PSE device 12 may be a high powered PoEmidspan device or it may be a PoE router or switch. Critically, the PSEdevice must be able to provide at least 100 W of DC power overlaid overan Ethernet data signal. Preferably there is provided over a single PoEconnection at least 200 W of DC power and more preferably between 200 Wand 600 W of DC power. The data signal that this power is overlaid uponmay be 10 Base T, 100 Base T & 1,000 Base T (Gigabit) or 10,000 Base T.Indeed, any future standard for Ethernet data/power transmission that iscompatible with the present invention is also claimed by the applicantto form part of the invention.

The PSE device are powered by high voltage 240/110 VAC power from apower source 16 which is generally located close to the data cabinets inwhich the PSE devices would be located. In most cases power supplied bypower source 16 is derived from the mains grid 18. It can, however, alsobe supplied by solar 19, wind 20 or battery 22. In the presentinvention, in order to provide a convenient and safe method of earthingremote PDU devices, an earthing system is provided which requires theproper earthing of the PSE 12 within a similarly earthed rack 24. Therack 24 is earthed via an earthing connection point 26 which is in turnconnected to multiple earths including earthed cable tray 28 anddistribution board 30. The cable tray 28 is in turn earthed byconnecting it to conductors located on the building columns (not shown)which are also accessible in the area under the access floor 34 or abovethe ceiling 36.

There is also depicted in FIG. 1 Ethernet cables for carrying the PoEconnections from the PSE 12 to the PDUs. The applicant has discoveredthat many types of Ethernet cables are unsuitable for carrying highcurrents associated with a combined DC power source of 200 W or more. Inthose cases, a high quality 23-gauge (or lower gauge cable) Cat6ashielded cable is the most appropriate choice for use with ahigh-powered PSE and a PDU. The cables manufactured and marketed byPanduit Corporation, an Illinois corporation from the USA are of veryhigh quality and capable of handling up to between 200 W and 300 W percable. In particular PFL6X04BU-CEG and PFL6X04WH-CEG manufactured byPanduit are suitable for implementation of the present invention as theydo not suffer from excessive temperature rises in the core of the cableand accordingly their safety and data transmission capabilities aremaintained as if they were running IEEE 802.3af, 802.3at or 802.3btstandards compliant PoE for up to 100 m span.

Multiple variations of PDU devices are shown in FIG. 1 . The first is an8 port PDU 38. This device shown in schematic form in FIG. 6 . Itreceives 8 high powered PoE connections 40 which are then drawn into thedevice where the DC power carried by the 8 connections 40 is introducedinto an inverter where it is converted into high voltage AC power forconsumption by a group of workstations. The 8 Port PDU 38 has an earthconnection 41 to the under-floor cable tray 28. As the 8 PoE connections40 also result in their being 8 available Ethernet connections after theDC power is removed, it is preferable that the 8 port PDU 38 service 8workstations so that each workstation is provided a combination ofEthernet connection and high voltage AC power 42 that is sufficient tomeet their needs. The Ethernet and AC power can be reticulated in the8-desk workstation in a number of ways. If the 8 Port PDU 38 has astarter socket 44 it can be connected to compatible soft wiring loomssuch as those manufactured by Electracom Pty Ltd trading as CSMElectracom or Schiavello Pty Ltd. The sorts of soft wiring options thatare available are shown in more detail in FIGS. 30 to 32 . In thesefigures the high voltage starter plug 44 is shown connecting to avariety of modular soft wiring accessories including T piece 440 forsplitting off a high voltage connection 442 that is sent to a desktopmodule 444 which provides a plurality of general power outlets 446.Ethernet cables 46 can also be run to the workstation module to providean Ethernet connection 450 for data connectivity. In addition to generalpower outlets the desktop module 444 also provides USB ports 448 forcharging. These can be provided by a USB power charger 452 which areplugged into general power outlets 454 which are placed inline in thehigh voltage, soft wiring assembly. Alternatively, USB outlets can beprovided for charging by the utilization of USB charging module 456 thatconnect inline with soft wiring general power outlets such as theintegrated USB module LEC-USB2 from Schiavello Pty Ltd which are shownseparated in FIG. 31 and connected in FIG. 32 . These modules can beintegrated into the workstation furniture together with outlets for theEthernet connections 46. Indeed, furniture integrated with soft-wiringlooms and connected to the 8 port PDU 38 is expressly contemplated asforming part of the present invention.

The 8 port PDU 38 also has a battery connection for connecting arechargeable battery 48. The purpose of this battery is twofold.Firstly, it is used as a backup reserve of energy for when the PoEconnections 40 become disabled or are disconnected. In such a case thebattery supplies a small amount of reserve energy to power the deviceand its connected devices for between 15 to 60 minutes. The secondpurpose is to take into account that peak loads may exceed supply atcertain times of the day or when devices are first turned on. Ratherthan increase the capacity of the system by introducing more PoEconnections 40, the peak demand that exceeds supply can be met from thebattery 48. In the present embodiment of a 1600 W 8 port PDU 38, anexample of a suitable 300 Wh battery is, model CU-J615, AAPortable PowerCorp of Richmond Calif.

The 8 port PDU 38 also has a sensor input for connecting sensors such asPIR 50. PIR 50 can be used to detect motion in the infrared spectrum.They are used to determine whether devices should be in a powered state.The PIR 50 is connected to the 8 port PDU 38 in two ways, firstly viadry contacts between the output of the sensor and the inputs of the PDUas well a power connection that provides low DC power for the sensorwhich is output by the PDU. Other alternatives to using a PIR to detectmotion around the area in which the 8 workstations are located is to uselight grids or rotating lasers to sense the presence of personnel, willoutput a signal to the 8 port PDU 38 to indicate to it that it shouldpower up the contained inverter. Such sensors could be located under thedesk such that when a person sits down they activate the inverter sothat high voltage AC power can be utilized by the desk's occupant. Otherpotential inputs that could be utilized are RFID readers which could beadapted to read the RFID chip contained within an employee's ID/accesscard. Further, as explained with respect to the communications protocoland particularly with the single port desk mounted PDU 52, a RFID readercould communicate the user information back to the building managementsystem for recording where the worker has been working which is usefulto know in agile workspace environments.

Turning to the single port desk mounted PDU 52 this is shown in FIG. 1being connected to PSE 12 via PoE connection 54. It is also shownconnected to underfloor cable-tray 28 as via earthing connection 56. Thesingle port desk mounted PDU 52 has two AC devices connected to it, alaptop 58 and monitor 60 via a laptop charger and a monitor power supply(not shown). The laptop is also connected to an Ethernet connection 62which is derived from PoE connection 54. The general power outlets 64derive their AC power from an inverter contained within the device. Thedevice also features a combined circuit breaker and residual currentdevice which have test and reset buttons 66 on the device for testingand resetting the RCD once it has been activated. The device alsofeatures a USB charging port 68 for charging devices such as phones andtablet computers. The single port desk mounted PDU 52 also incorporatesa sensor unit for connecting sensors such as PIR's as describedpreviously with respect to the 8 port PDU 38. FIG. 1 depicts RFID reader68 which is powered by and connected to PDU 52. In order to keep the ACpower operating, the RFID reader 68 needs to be activated at regularintervals otherwise it turns the inverter off and all AC poweredequipment will not be able to operate. Also shown is luminaire 70 whichis an LED powered by PoE power and supplied via RJ-45 jack as describedin Australian Innovation Patent Number 2016100103. Switches for theluminaire 70 and AC devices are incorporated but not shown. An externalbattery pack 72 is also shown. It is used in the same way as battery 48.The battery is a 10.8v 4.5 Ahr NiMH-Battery such as Model No:TEB-BAT-PACK-DM161HD from Master Instruments Pty Ltd(www.master-instruments.com.au). It would last about 20 minutes whensupplying 200 W of power to the PDU 54.

Also shown in FIG. 1 is a docking station PDU 74 which is connected tothe PSE by way of PoE connection 76. It also has an earth connection 75.The docking station PDU 74 differs significantly from single portdesktop PDU 52 in a number of ways. Firstly, it has onboard video whichdrives a plurality of digital video ports 76 which include HDMI and DVI.These are used to drive monitors 78 which are in turn powered by generalpower outlets 80. The power for the outlets 80 is derived from aninternal inverter connected to a PoE splitter and where the AC power isoutput via an integrated RCD and circuit breaker. The Ethernetconnection is also output via RJ45 jack 82. The docking station also hasan on board a microcontroller that controls the input and outputmodules. Computers 77 such as laptops are powered via an adaptorconnected to a source of DC power including USB-C port 84 which has USB3.1 specifications that allow up to 100 W of power at 20V to be used tocharge and power devices. It is connected for communications via asimilar USB3.single port 73. A bank of USB2 ports 75 are also provided.In the docking station PDU 74 the battery is internal to the device andfurther, the device does not have contacts for connecting externalsensors. Rather, an internal RFID reader 71 is included internally thatis adapted to be activated by employee security/access cards andfurther, to monitor and report back the power consumption by referenceto the identifications used thereby providing a means to generate anindividual report for a person's energy consumption over time even ifthey swap desks as is common in hot desk environments. U.S. Pat. No.8,990,469 for a portable electronic device docking station, which isincorporated herein by reference, discloses many of the components ofthe present docking station, and can be used as a guide.

Also shown in FIG. 1 are lighting PDU's 88. They are connected via PoEconnections 90 and earthing bonds 93. They are connected to LEDluminaires 92 and 94. The luminaires can in fact be any light fixturethat can be powered by AC power, where said power is provided by thelighting PDU 88's internal inverter. In the case of luminaire 94, itsonly connection is via the general power outlet of lighting PDU 88. Theon-board microcontroller is adapted to turn the inverter on and offthereby control the operation of the luminaire. Alternatively, inembodiments without an onboard microcontroller, the luminaire can becontrolled by turning off the power to the PSE port via SNMP commands.With respect to luminaire 92 this is shown connected to the lightingPDU's 88 external DALI outputs as well as to the general power outlet.The DALI outlets allow signals to be sent to the luminaire in order tocontrol its brightness and color and whether it is off or on. LightingPDU's 88 also are connected to or contain internally, battery 96 and arealso connected to a roof mounted ceiling tray 98 at earth bonding points93.

There is also depicted in FIG. 1 a series of daisy-chained LED battens102 and a maintained emergency luminaire 104 connected by a single PoEconnection 99. Close variants have been described in AustralianInnovation Patent Application 2016100103. The material differences onlyrelate to the control and command technologies embedded within themwhich will be discussed later in the specification after that concepthas been introduced.

Other devices that can be powered and connected to PSE 12 include CCTVcamera 106 and Wi-Fi access point 108. Such devices do not require thehigh amount of power made available through the PoE connections.Notwithstanding that Wi-Fi base station 10 can be used to communicatewith remote devices including PCs 110. Indeed, PSE 12 can directlycommunicate to PC's 112 via a directly wired Ethernet connections.

Signaling System

The forgoing was a description of various PSE and PDU apparatus usefulin PoE systems for delivering power, light and data as services tobuilding occupants. The following passages will focus primarily on asignaling system that can be implemented in the apparatus describedpreviously.

The existing method for signaling between PSE and PDUs either involvessimple, but limited, passive methods, such as, identification resistorsor Layer 2 Ethernet protocols which, by their nature, requiresubstantial accommodation within the particular technical standard (IEEE802.3 af, at or bt).

The applicant proposes an alternate signaling method that can operatesimultaneously alongside the existing ethernet protocol without anyinterference. It also offers an alternative mapping of PoE services suchgeneral purpose outlets or lighting points that are logically mappedaccording to their physical configuration. That is, control such as;lighting circuit dimming, remote sensing or General Purpose Outlet (GPO)mains power control is based on which particular PoE port that device isconnected to, therefore, negating the need to enter Internet Protocol(IP) addresses for every PoE component that is to be connected to andcontrolled by the system.

The present signaling system is designed to operate on existing 10 BaseT, 100 Base T & 1,000 Base T (Gigabit) as well as 10,000 Base T (10Gigabit) Ethernet systems with no interference to the high-speeddifferential signaling (transverse signaling) of the data.

In existing PoE systems unused pins (in the case of 10 Base T & 100 BaseT) are often used to carry a steady direct current signal from the PSEto the PDU. In the case of 1,000 Base T (Gigabit) and 10,000 Base T (10Gigabit), as well as many 10 Base T & 100 Base T PoE applications, thesedirect current signals are superimposed onto the differential signal ina common fashion. In other words, a DC signal is injected onto theethernet cable by providing a high-current path to both sides of thedifferential signal. In this scheme, half the DC injected signals arefed from the positive terminal of the PSE power supply (rectifier) andthe remaining half are fed from the negative half of the power supply.

The common-mode (longitudinal) control signal of the present inventionis injected in a similar way to which the DC signal is injected in thePower.

Source Equipment (PSE). That is, the control signal, from a modem, isfed via transformer which is then superimposed onto the DC signal bycreating a small ripple or perturbation (typically hundreds ofmillivolts in amplitude) of the DC injected signal. This signal is inturn recovered from the Power Distribution Unit (PDU) via a similartransformer and feed in modem.

The forgoing is best explained by reference to FIG. 2 in which there isshown an example of an electrical construction of a PoE interface as itwould typically be implemented to provide the desired signalingcapability between PSE and PDU. The figure depicts PoE injector 200 thatforms part of the PSE 201 and PoE splitter 202 that forms part of thePDU 203. FIG. 2 further depicts a single Ethernet Cat6a shielded cable206. It should be noted that the figure shows the cable 206 includes 9total conductors, including four twisted pairs (which are commonly foundin all Ethernet cables) and conductor 208. Conductor 208 will bereferred to in subsequent passages that deal with the issue of earthing.Suffice for present purposes that the ninth conductor does not play anypart in the signaling system of the present invention. In this figurethe signal from modem 210 is fed into a transformer 212 whose secondaryis used to perturb the direct injected current which is supplied by theDC power supply 214. An overcurrent protection device 213 (such as,LittleFuse model RXEF300) has been placed in the power supply to protectthe system in the case where the PDU attempts to draw excessive currentfrom the PoE Ethernet connections.

Also referring to FIG. 2 the introduced signal is recovered from the bythe transformer 214 which is then demodulated by modem 216. In both thePSE 201 and PDU 203 side of FIG. 2 the method of direct current andmodem common-mode (longitudinal) signal injection is achieved by way oftapped ethernet transformer. Whilst this approach is the most commonmethod of implementing this longitudinal signal injection, it is not theonly method.

Referring to FIG. 14 an alternative method of longitudinal signalinjection is achieved by way of a tapped choke which is physicallyseparate from the ethernet transformer. It is customary, although notmandatory, to also included DC (direct current) blocking capacitors inthis configuration to avoid stray DC currents saturating the associatedethernet transformer. Note that the direct injected current in thisapproach is perturbed by injecting the modem signal into the positiverectifier supply.

Referring to FIG. 15 the method of longitudinal signal injection isagain achieved by way of a tapped choke, but the perturbation signal isachieved by injecting the modem signal into the negative rectifiersupply.

Referring to FIG. 16 , an alternative method of longitudinal signalinjection is achieved by way of two separate chokes which again isphysically separate from the ethernet transformer. Once again, it iscustomary, although not mandatory, to also included DC (direct current)blocking capacitors in this configuration to avoid stray DC currentssaturating the associated ethernet transformer. Note that the directinjected current in this approach is perturbed by injecting the modemsignal into the positive rectifier supply.

Referring to FIG. 17 , it shows the method of longitudinal signalinjection is again achieved by way of a separate chokes, but theperturbation signal is achieved by injecting the modem signal into thenegative rectifier supply.

PSE and PDU with Signaling

Turning to FIG. 3 there is depicted a high-level, simplified (only twopairs of the Ethernet cable shown) block diagram of the PSE 201 majorcomponents including PoE Injector 200, modem 210 and transformer 212.The transformer 212 is connected to the modem 210 which sends variouscommands that are derived from PSE microcontroller 218 and in turn aregenerated in the PSE microcontroller 218. The demodulation of theinjected longitudinal commands is performed in the PDU modem 216.However, as the communications link is bi-directional, the same is truein the reverse when the PDU is transmitting signals to the PSE. The PSE201 can be configured and interrogated via a control port 220. Theprotocol for this management port is based on the industry standardSimple Network Management Protocol (SNMP).

Imbalances in the injected DC signal can occur due to faults in theCAT6a ethernet cable and/or connector terminations. To ensure that eachof the terminals on the ethernet connector and each conductor on theCAT6a cables is passing its share of the injected current to the PowerDistribution Unit (PDU) a current balance measurement has beenimplemented using multiplexor switch 222. The current imbalance isdetermined by measuring the voltage drops across the resistors ininjector 200. The common of the multiplexor switch is feed to ananalog-to-digital convertor in the PSE controller 218. If the currentimbalance is only mild, then a warning can be issued via the controlport 220 if the imbalance is large then the injected power may bereduced so that the system operates within safe limits.

Preferably, modems 210 and 216 use a frequency modulated carrier toencode data, otherwise known as Frequency Shift Keying (FSK). Tofacilitate full duplex communications each modem may operate on separatecarrier frequencies. However, it is preferable to operate at half-duplexas this mode enables many more devices to be paralleled off each port.Also, if only half duplex communications are required then both modemscould operate at the same carrier frequency. Whilst the modemspreferably use a frequency modulation carrier(s), alternative modulationschemes are possible such as, phase, amplitude, pulse position, orManchester coding. Alternatively, both the phase and amplitude may bemodulated in schemes such as Quadrature Amplitude Modulation (QAM). Asthe amount of data transferred longitudinally across the link is onlyminimal, various low-baud-rate commercial modem standards are suitable,such as, Bell 103, Bell 202, or V22.

Protocols

Various commercial communications protocols are suitable for thelow-speed longitudinal signaling. As low-cost micro-controllers oftencontain in-built Universal Asynchronous Receiver Transmitters (UARTs) anasynchronous byte-oriented protocol is preferred. However, thissignaling could also be implemented using synchronous techniques and/ora bit wide protocols.

Preferably, asynchronous framing using a single frame version of theHigh-level Data Link Control (HDLC) as described in ISO 3309. The packetstructure is given in FIG. 1 . There are seven fields within theprotocol, namely; Frame (start byte), Address (two bytes), Type (onebyte), Length (one byte), Payload (variable length from 0 bytes to65,535 bytes), CRC-8 (one byte), Frame (end byte).

Each message is framed with a start and an end byte using a unique byte,typically 7E_(hex) or 01111110 binary is typically used as a frame byte.Should this byte be required in the payload it needs to be bounded withan escape character. If the escape code is required in the payload anadditional escape character is stuffed into the payload.

The advantageous features of this protocol include; a very simple andgeneric message structure, with error detection using a single byteCyclic Redundancy Check (CRC-8), protocol level handshaking using theACK (acknowledge) and NACK (not-acknowledge). Each message contains anaddress which enables up to 255 devices to be separately addressed oneach port, thus enabling multiple devices to be either paralleled oreven daisy chained onto each port (e.g. an inverter, a lightingcontroller, emergency light). It is important to note that the Ethernet(IEEE 802.3) interface does not normally support multi-dropconfigurations on its differential (transverse mode) signaling as thehigh data-rates need accurate line termination to the characteristicimpedance of the cable, however, the common (longitudinal-mode)signaling operates at a much lower carrier frequency and is thereforemuch more tolerant of non-ideal line termination, thus enablingmulti-drop configurations.

It is advantageous for the longitudinal signaling to be modulated at alow baud rate as this dramatically reduces the line terminationrequirements from short port cable runs of up to 100 meters. Whilst apeer-to-peer communications link has certain advantages, such asevent-initiated communications it is more advantageous to use amaster-slave protocol as the command data direction largely emanatesfrom the PSE to the PDU. In a master-slave configuration the PSEinitiating communications with the various PDU devices connected to eachof the PSE ports.

To facilitate the various control functions that are initiated from thePSE a variety of message types are called for. Within the preferredimplementation there are up to 255 message types available for eachendpoint to implement comprehensive communication. A subset of thesemessage types is given in Table 3.

TABLE 2 Command/ Frame Address Type Length Payload CRC-8 Frame 1 Byte 1Byte 1 Byte 2 Byte x 1 Byte 1 Byte

TABLE 3 Type Description Response Payload 0 Command/Data Ack/(Ack,Data)/Nack/ (Ack, Unknown Command) 1 Ack Null 2 Nack Null 3 UnknownCommand Ack/Nack 4 Node check (ping) (Ack, pong)/Nack 5 Node response(pong) Ack/Nack 6 Status? (Ack, Status Response)/Nack 7 Status ResponseAck/Nack 8 Node type 9 Node type response Ack/Nack A Time Set Ack/Nack BBroadcast for Nodes Node Response (pong)

A subset of the particular commands that control the various peripheraldevices that are connected to the PSE is summarised in Table 5. Thesecommands are focused on the controlling and monitoring theGeneral-Purpose Outlets (GPOs), lighting circuits and sensors (such as,light curtains and passive infrared (PIR) movement sensors).

These commands are transported in the packet payload. An example, wherethe status of the invertor is requested is given in Table 6 with theassociated response given in Table 7.

In another example involves PoE enabled lighting where message is sentto set the dimmer value to 50%, Table 8 with its associated response inTable 9.

TABLE 4 Payload for Command/Response: Payload Type Payload Subtype Data1 Byte 1 Byte 0-65533 Bytes

TABLE 5 Command/Response payload list: Payload Command/Response PayloadType Subtype Data Size Light off 0x01 0x01 Null Light on 0x01 0x02 NullDim to x 0x01 0x03 1 Byte Dim to x 0x01 0x04 2 Bytes at rate First Byte:setpoint Second Byte: Rate Max dim 0x01 0x05 1 Byte Min dim 0x01 0x06 1Byte Inverter 0x02 0x01 Null status req Inverter 0x03 0x01 5 Bytesstatus res 1st Byte - V out 2nd Byte - I out 3rd Byte - Temp 4th Byte -Batt status 5th Byte - ELCB status Inverter 0x02 0x02 Null output onInverter 0x02 0x03 Null output off Sensor Read 0x04 0x01 Null req Sensorread 0x04 0x02 2 Bytes res

TABLE 6 Example Inverter control (Inverter at address 1): Message fromPSE: Request Inverter Status CRC- Frame Address Type Length Payload 8Frame 0xAA 0x01 0x01 0x02 0x0201 # 0x55

TABLE 7 Response from PDU: Inverter Status CRC- Frame Address TypeLength Payload 8 Frame 0xAA 0x01 0x01 0x07 0x0301xxxxxxxxxx # 0x55

TABLE 8 Example light control (Light at address 2): Message from PSE:Dim to 50% CRC- Frame Address Type Length Payload 8 Frame 0xAA 0x02 0x010x03 0x010380 # 0x55

TABLE 9 Response from Light: Ack Frame Address Type Length CRC-8 Frame0xAA 0x02 0x02 0x0 # 0x55PDU

Having addressed the basic structure of a PSE including its PoE injectoraccording to the present invention, and the protocols and commands thatare capable of being transmitted over the link between PSE 201 and PDU203 attention will now turn to the general structure of a PDU beforeturning to specific PDU embodiments depicted in FIG. 1 .

Referring to FIG. 4 there is depicted a generalized PDU 203 containing aPoE splitter 202 which includes modem 214 and transformer 216. In asimilar fashion to that which was described with respect to PSE 201, thePDU 203 has a PDU microcontroller 224 which is in communication with themodem 214 of PoE splitter 202. Received signals from the modem aretransmitted to the PDU microcontroller 224. Control port 224 can also beused to communicate with PDU 203 locally via a technician's computer.However, in practice it would be rarely necessary to access this featureas the PDU and its connected devices can be controlled remotely via thesignaling system of the present invention.

These core components form the base configurations of any PDU 203,particular for those that run on only DC power and that do not requirethe inclusion of an inverter such as luminaires 102 and 104 from FIG. 1.

However, for the majority of PDU's disclosed presently, they all have aninverter 226 which converts the DC power collected from the PoEconnection by PoE splitter 202 and converts it into high voltage ACpower for outlet via either general power outlet 234 or a compatiblesoft wiring starter jack (not shown). This allows PDU devices to be usedto carry both power and data to workstations and pluralities ofworkstations which obviates the need to install high voltage cabling.RCD/circuit breaker 238 is installed so as to protect or reduce the riskof any end user being injured or killed through accidentalelectrocution. Switch 236 is utilized to turn the inverter on and off.

In certain embodiments further services and functions are performed bythe PDU 203. These include providing a battery 228 for uninterrupted useof connected devices when the PoE connection becomes disabled. Thebattery also provides additional energy to accommodate peaks in demandthat exceed supply provided by the PoE connection. Battery 228 has anintegrated temperature sensor. The battery 228 is connected to chargecontroller 230 which regulates the flow of power between battery 228,USB charger 232 and inverter 226. USB charger 232 is provided so as toprovide a USB port to charge devices. Various USB standards can beutilized including USB 3.1 which can provide 100 W of DC power. Asdiscussed with respect to PDU 88 and 52 of FIG. 1 , the PDU's can alsodrive lights via legacy command systems including DALI and DSI via thelighting controller 234. Lighting controller also outputs DC power fordriving LED lights directly including dimming and color changingabilities.

PDU's 203 can also have sensors attached to them that make the use ofthem more energy efficient. For example as described by reference toFIG. 1 , sensors can be used to determine the proximity of human usersand in the absence in the presence of any humans or movement, theinverter and/or any connected luminaires can be shut down. Manydifferent types of sensors can be connected including PIRs, light grids,rotating lasers and RFID readers. In the case of RFID readers thesewould need to be integrated via a I/O function of the PDU controller 224as opposed to the dry contacts that the other sensors can operatethrough. PDU also has a low voltage/low power output (5-10V/10 W) forpowering sensors and other low voltage equipment such as VOIP phoneswhich typically consume less than 10 W of power.

As mains voltage circuits need protective earth connections such as theMains Earthed Neutral (MEN) system which has been adopted in mostcountries there is a need to provide a protective earth connection toeach PDU 203. There are two methods available; the first requires that aseparate earth conductor be run from an earthing stud 240 located on thePDU 203 case.

Alternatively, a protective earth can be run using either a modifiedCAT6a cable that includes a separate earthing conductor 242 (see item520 in FIG. 35 ) or alternatively via a standard shielded cat6a cablevia its foil shield (see item 522 in FIG. 36 ). An example of such acable or cables are Cat6A made by Panduit Corporation includingPFL6X04BU-CEG and PFL6X04WH-CEG. This ninth conductor, shown in FIG. 2as item 208, is brought into electrical contact with both the externalearthing plug and also the inverter 226, RCD/circuit breaker 238 and ACpower outlet 234.

There are two methods of using the ninth conductor 208 as a functionaland protective earth. As a protective earth the connection to earthneeds to be the made first before any of the active power carryingconnections are made when inserting the plug containing the earth, andthe last connection broken when removing the plug. To accommodate thisadditional conductor a modified M12 Ethernet plug 244 has beendeveloped. An example of this modified M12 Ethernet bulk-head socket isshown in FIGS. 19 to 21 . In these figures the additional earth receptor246 can be seen in the center of the cluster, making 9 connection poles(8 for the 4 twisted data/power pairs and the remainder for theprotective earth). Likewise, the associated inline plug 248 also has 9pins shown in FIGS. 22 to 24 . Note the extra-long earth pin 250protruding past the other 8 signal/power pins seen in FIG. 24 . Theninth conductor, whether it be a ninth conductor of a modified Cat6acable or the shielding on current Cat6a cables, is connected to theninth pin 250 which connects to ninth receptor 246. At the PSE end, theM12 connector 246 is bonded to the rack which is in turn bonded by wayof metal screws to the multiply earthed rack.

In the alternative, if a modified M12 is not utilized, certain RJ-45systems can be incorporated to provide earthing back to the rack whichin turn is earthed back to multiple earths and distribution boards asshown in FIG. 1 . These include the shielded copper cabling system madeavailable by Panduit Corporation that include models PFL6X04BU-CEG andPFL6X04WH-CEG. Importantly the range includes: (i) shielded jacksincluding CJS6X88TGY that have 360 degrees conductive covers, (ii)shielded plugs TX6A, patch panel assemblies CPA72BLY and otheraccessories including bonding screws RGTBSG-C and common bonding networkjumper kit RGCBNJ660P22. Using the shielding of the Panduit Cat6a23-gauge cable makes it very easy to provide an earth to the PDU. Insuch cases where the requirements of a protective earth are met,separate earthing connections to external earthing lug 240 may not benecessary and can be avoided. Further all that is required to effectthis grounding system is to use the appropriate cable, jacks and plugsand provide a connection at the PDU end between the components requiredto be earthed and the patch panel which is in electrical contact withthe jacks outer covering which in turn are in contact with the plugsexternal metal conductors.

Reference is now made to FIGS. 33 and 34 which both depict CAT6a cablescross-sections that are co-located (FIG. 34 ) or joined directly (FIG.33 ) with a dedicated insulated earthing conductor. These twoembodiments will not typically be terminated through either an RJ45 orM12 plug as a single termination point but rather require the cable tobe separated at the PSE end and the dedicated earth conductor connectedto grounded or earthed fixtures such as the communications rack the PSEis mounted as shown in FIG. 1 by reference to connection 21 where thePoE connection is shown forking between the PSE 12 and the rack 24,using, for example “Structured Ground Common Bonding Network JumperKit”, part #RGCBNJ660P22 made by Panduit Corporation. Other possibleearthed fixtures such as cable trays, pipework, columns could also beused as an earthing target and these need not be at the PSE end butanywhere in between the PDU and PSE.

Attention is now turned to inverter 226 and inverters generally for usein PDU devices. The typical equipment that is used in an agileworkspace, namely; laptop computers, printers, VoIP phones, screens etc.(see Table 1) where the device power supply is based on switch modetechnology, as such there is little need for a pure sinewave AC outputvoltage, as the first step in most switch mode supplies is to rectifyand store the main signal. Preferably the AC output of the of a PDUinverter voltage would be either quasi-sinewave or even square wave asinverters built around these topologies are inherently more efficientthat those that provide pure sinewave output.

The Alternating Current output from inverter 226 is feed into theResidual Current Device 238 which also includes an integratedover-current circuit breaker. If the current imbalance between theActive and Neutral lines generated in the inverter 226 does not exceed30 mA (or similar regulatory safety value) and the current is less thanthe over-load value then the RCD 238 will pass the inverter's power tothe GPO 234.

It is preferable if the overcurrent protection element (circuit breaker)of the RCD 238 is rated slightly higher than the invertor's internalover-current limit so that a minor over-load will not trip the circuitbreaker but rather only trip the invertor. It is preferable if theinvertor's internal over-current protection would reset once the loadfault is cleared. Even more preferable, is the use of an invertercircuit that also incorporates a thermal overload in case the thermaldissipation of the Power Distribution Unit (PDU) is compromised byrestricted air supply or elevated ambient temperature. Fans andheatsinks are the most appropriate methods of minimizing the probabilityof this occurring. It is preferable that the inverter operates at anambient temperature between 10° C. to 60° C. and that the energyconversion efficiency is at least 90% to reduce the need for activethermal management.

To reduce the risk of excessive and dangerous currents circulating backfrom the general-purpose output (GPO) connected circuit to the PDU andPSE the inverter should incorporate an isolated output. Apart fromisolation, the inverters should also have the ability to report variousperformance measurements such as, output voltage, output current,temperature of main switching elements as well as the battery voltage. Alarge number of commercial inverters and un-interruptible power suppliescome with these capabilities.

As mentioned previously, control port 220 operates using the SimpleNetwork Management Protocol (SNMP). The interface for the control portcan be either local technician's computer or alternatively this acentrally located management computer. An example of the packet that issent and its response when an SNMP query, of the inverter status isgenerated is given below in Tables 9 and 10 respectively:

TABLE 10 Example Inverter control (Inverter at address 1): Message fromPSE: Request Inverter Status CRC- Frame Address Type Length Payload 8Frame 0xAA 0x01 0x01 0x02 0x0201 # 0x55

TABLE 11 #Response from PDU: Inverter Status CRC- Frame Address TypeLength Payload 8 Frame 0xAA 0x01 0x01 0x07 0x0301xxxxxxxxxx # 0x55

The invertor status information is given in the response payload whichsummarised in the table excerpt below:

TABLE 12 Inverter 0x03 0x01 5 Bytes status res 1st Byte - V out 2nd Byte-I out 3rd Byte - Temp 4th Byte - Batt status 5th Byte - ELCB status

Communication with the inverter enables each of the condition of theinverters in the various PDUs to be remotely interrogated by buildingmanagement software.

Discussion now turns to FIGS. 25 to 27 which depict a number ofalternative embodiments for a multi-port PDU. A multi-port PDU is one inwhich multiple PoE connections are converted into a single source ofhigh voltage AC power. This is an excellent alternative to buildingbespoke high-powered injectors as off the shelf components can beutilized. However, there are significant drawbacks and problems withsuch an approach as will be noted below.

Common to all embodiments of the PDU are four Ethernet ports 254 whichreceive PoE connection and split it into data and power via splitter256.

The obtained DC power is then in the case of FIG. 25 paralleled to forma high current, low voltage DC power source for feeding into inverter258. The produced high voltage AC is then fed into is derived using aTycon PoE splitter model PoE-INJ-1000-DINx. Together these four PoEports can provide 480 W of power.

In the case of the circuit in FIG. 26 , the circuit realization requiresa PoE splitter than has an electrically isolated output (such as, TyconPoE splitter model PoE-INJ-1000-DINx) in order to create a high voltageDC power source for supplying the inverter. The use of these devicesisolates the outputs, which however result in additional losses andconsequently more heat and lower efficiency.

Referring to FIG. 27 , an alternative topology is proposed where theoutputs from each of the PoE splitter 256 are independently feed intofour separate inputs of a universal input invertor (such as,CyboEnergy—CyboInverter Model Ci-Mini-100Te). Whilst this approach hassome merit it is not as efficient as the topology shown in FIG. 25 whichis the preferred topology.

Notwithstanding that the topology in FIG. 25 is preferred over FIG. 26and FIG. 27 , there are significant shortcomings. In particular whenusing a multi-port PDU, it is imperative that the devices, including thePSE are constructed in a way that does not permit the power ratings ofthe cables utilized to be overpowered. This is a particular problem formulti-port PSE's when used with multiport PDU's. If precautions are nottaken, the power that runs over 4 cables could suddenly be applied to asingle cable, leading to overheating and fire which would be potentiallycatastrophic.

Accordingly, newly proposed designs for a multi-port PSE and multi-portPDU have been developed are depicted in FIGS. 5 and 6 respectively.

Turning to FIG. 5 there is depicted a multi-port PSE or midspan 400which is preferably made in a rack-mounted form factor. It is depictedwith a single DC power supply 402 which could be supplied by many offthe shelf DC rack-mounted DC power supplies including the Sentinel PowerSystem SRS-48 manufactured in California by Newmar(www.poweringthenetwork.com) which outputs 1600 W DC at 57V over asingle output. The DC power supply is applied to a bank of currentlimiting devices 213, which are also set out in FIGS. 2 and 3 , whichreside in each of the PoE injectors 406 which serve the purpose ofputting an upper limit on the amount of current that is drawn from DCpower supply 402.

The DC current is then passed into PoE Injectors 406 of the kind shownin FIGS. 2 and 3 . These are in communication with PSE controller 408which in turn is in connection with control port 410. PoE Injectors 406also receive Ethernet signals from Ethernet port 412 and the combinedPoE Ethernet and DC power is output as an PoE connection over Ethernetport 414. The patch panel 416 and Ethernet ports 414 re of theshielded/grounded variety previously described. These are in turnconnected to rack 418 which is grounded and forms a path to earth forthe ninth conductor in the cables connected to Ethernet ports 414. Asdescribed with reference to FIGS. 2 and 3 , the injection of high-powerDC signal of at least 100 W is required for the proper operation of theinvention. Preferably at least 200 W is injected into the PoE signal.Even more preferably between 200 W and 300 W would be injected.

In the case where the injection voltage can be elevated from 57 VDC (thelimit under IEEE802.3af,at,bt) to 120 VDC (the Extra Low Voltage limitunder the ASNZS3000 electrical safety standard which being similar tomany other regional standards) which equates to a PoE transfer power of460 W per PoE channel.

In the case of 8 port PDUs a preferred 1600 W DC power budget would berequired. Turning back to the need for power limiting devices located ininjectors 406, if half (4) of the cables carrying 200 W weredisconnected, without the current limiting devices, the four cablesworth of power would begin to flow through the remaining cables. Thiswould probably be sufficient to overheat the cable and cause it to catchfire. One way to avoid this is to employ a multi rectifier DC powersupply that outputs a plurality of load limited DC power supplies suchas MST Power's 488-27 which is a DC power supply with 9 hot swappablerectifiers which offer 8+1 redundancy and 8 individual sources of 200 Wof DC power. If such a power supply is used, then the current limitingdevices can be omitted, and each injector of PSE 400 would beindividually fed 200 W.

Turning to FIG. 6 there is depicted an 8 port PDU 420. The 8 port PDU420 features patch panel 417 which is in electrical contact with 8ethernet jacks 418 which in turn into 7 PoE splitters 424 of theconventional type—with no onboard means of communication unlike those inFIG. 3 ; patch panel 426, Ethernet jacks 428 (shielded) of the sortpreviously described from Panduit Corporation. There is also providedone master PoE splitter 429 of the kind set out in FIG. 4 which is incommunication with PDU controller 430. PDU controller 430 is also incommunication with sensor input 417 432 and control port 431. The DCpower supply obtained from the PoE connections is taken and fed into theinverter 433. The outputs of the inverter 433 are high voltage AC powerwhich is passed to RCD/circuit breaker 438, then on to outlet 439 whichmay be a soft-wiring starter module or it may be a general power outlet.Battery 435 is provided for backup power and to meet peak demands. Thiswould include batteries 48 previously referred to in FIG. 1 .

Reference is now had to FIG. 18 which depicts a power supply 460 in arack 462, a plurality of PSE 464 and a network switch 466. The PSE 464devices each have 16 high powered PoE connections available in its 16ethernet ports 468 as well as a single control port 470 on each midspanPSE 464. Each control port is in turn connected to hub 472 the mastercontrol port 474 is then patched into the switch 466. As each controlport on each PSE 464 only controls those devices connected to that PSE,a method of controlling all connected devices includes accessing themaster control port remotely via the switch. More specifically acomputer on the network made available by switch 466 will be able toaccess the building management software which is served via a server inthe network. The user accesses the software then makes the necessarychanges or issues commands which the building management softwareinterprets and turns into control commands sent to the PDU in accordancewith the invention.

Reference is now made to FIGS. 7 and 8 and 9 which show various views ofa workstation PDU 476 which was not depicted in FIG. 1 . The principaldifference between this embodiment and the workstation PDU 52 is thatPDU 476 does not have any sensor inputs or ability to hook up externalLED lights or control lights using DALI/DSI. The PDU 476 does, however,share test and reset buttons 478 associated with the RCD, two GPO's 480.A USB3.1 charging port 482 and 10/1000 Base T Ethernet port 484. Theport for connecting a battery is shown as 486 on a side view in whichthe unit has been mounted on a desk 486. Also shown on the rear aremodified M12 input 490 and RJ-45 input (shielded and conductive) 488 aswell as an earth connection point. This embodiment of PDU 476 is mostuseful when there are no luminaires to drive and control and/or when asimple under-desk solution that can be used to complement and connectwith soft-wiring modules and accessories. In such a case it is alsopossible to replace one or both of the GPO's with a soft-wiring starterjack.

By contrast the PDU 494 is consistent with the workstation PDU 52 fromFIG. 1 . Many of the ports are the same as the previous PSU however itshould be noted that PDU 494 includes LED outputs 495 for drivingexternal LED luminaires, DSI 496 and DALI 498 outputs for controllingluminaires that only respond to DALI and/or DSI commands. The PDU 494also features a sensor power output 499 and sensor dry contacts 500. Itshould be noted that the sensor power output 499 is very low watts andlow voltage. This makes it suitable to use as a source of power for lowpowered devices such as VoIP phones.

Referring to FIGS. 12 and 13 these correspond with the lighting PDU's 88from FIG. 1 . They differ from the earlier two PDU's in that they lackEthernet out and USB charging points. As these are only designed toservice luminaires there is no need to have these components.

Reference is now made to FIGS. 28 and 29 which depict the LED daisychainable luminaires 504 and 503 (102 and 104 from FIG. 1 ). These arethe only PDU devices that have been presently disclosed without aninverter. They do however run on PoE connections which are introduced inRJ45 506 and the split/duplicated in T piece 508. One of the PoEconnections is passed to PoE port output 518 for connecting the nextluminaire. The other PoE connection is passed to PoE splitter 510 of thepresent invention as in the case of FIGS. 2 and 4 which havecommunications/signaling ability provided by microcontroller 512 whichdrives lighting module 514 which in turn drives LED strips 516. Theluminaire in FIG. 29 contains, additionally, a charge controller 520 andbattery 522 for keeping the LED strips on even in the event of powerfailure.

INDUSTRIAL APPLICABILITY

The present invention has applicability in the area of office fit outs,building construction and the provision of electrical, data and lightingservices.

The invention claimed is:
 1. A power distribution unit for outputtinghigh voltage AC power, the power distribution unit comprising anEthernet port configured to receive an Ethernet cable, wherein theEthernet cable is configured to provide low voltage DC power from apower source to the Ethernet port; at least one additional Ethernet portconfigured to receive an associated at least one additional Ethernetcable, wherein the associated at least one additional Ethernet cable isconfigured to provide low voltage DC power to the at least oneadditional Ethernet port; an inverter to receive a combination of thelow voltage DC power received from the Ethernet port and the low voltageDC power received from the at least one additional Ethernet port, and toinvert the combined low voltage DC power to provide the high voltage ACpower; an electrical connection to ground; an AC outlet to provide thehigh voltage AC power and the electrical connection to ground to devicesconnected thereto; and a residual current device (RCD) connected to theAC outlet for monitoring the high voltage AC power of the AC outlet anddisabling the high voltage AC power from the AC outlet when a power leakis detected.
 2. The power distribution unit of claim 1, furthercomprising a USB port to receive a USB cable associated with a USBpowered device and power the USB powered device, wherein the USB portderives power from the low voltage DC power received by the Ethernetport.
 3. The power distribution unit of claim 1, wherein the Ethernetcable is further configured to provide to the Ethernet port networkingsignals from a network in conjunction with the low voltage DC power, andfurther comprising a splitter for separating the networking signals andthe low voltage DC power; and a network interface for connectingnetworkable devices to the network and providing the separatednetworking signals thereto.
 4. The power distribution unit of claim 3,wherein the network interface is a network Ethernet port.
 5. The powerdistribution unit of claim 3, wherein the network interface is awireless communications module.
 6. The power distribution unit of claim1, further comprising a soft wiring interface for connecting devicespowered by AC power to the high voltage AC power, wherein the softwiring interface includes one or more soft wiring cables and one or moresoft wiring modules connected to the one or more soft wiring cables oranother soft wiring module, wherein the soft wiring interface conductsthe AC power to the devices powered by AC power.
 7. The powerdistribution unit of claim 6, wherein the one or more soft wiringmodules include one or more soft wiring general power outlets.
 8. Thepower distribution unit of claim 1, further comprising a battery forproviding DC power to the inverter when the low voltage DC powerprovided to the inverter by the Ethernet port is insufficient to meetdemand for power.
 9. The power distribution unit of claim 1, wherein theAC outlet provides at least 800 W of the high voltage AC power.
 10. Thepower distribution unit of claim 1, wherein the electrical connection toground is provided by a ground connection lug.
 11. The powerdistribution unit of claim 1, wherein the electrical connection toground is provided by the Ethernet cable, wherein the Ethernet cableincludes four twisted pair of insulated conductors and a ninth insulatedconductor, wherein the ninth insulated conductor is used to provide thepower distribution unit with a connection to protective earth includedin the power source.
 12. The power distribution unit of claim 11,wherein the four twisted pair of insulated conductors and the ninthinsulated conductor are located within a single housing.
 13. The powerdistribution unit of claim 11, wherein the four twisted pair ofinsulated conductors are located within a first housing and the ninthinsulated conductor is located within a second housing, wherein thefirst housing and the second housing are secured to one another.
 14. Thepower distribution unit of claim 13, wherein the first housing and thesecond housing are co-located within a third housing.
 15. A method ofproviding high voltage AC power to a remote site via a powerdistribution unit that includes an Ethernet port, at least oneadditional Ethernet port, an inverter, an AC outlet and a residualcurrent device, the method comprising: receiving, at the Ethernet port,an Ethernet cable providing low voltage DC power and an electricalconnection to protective earth from a power source; receiving, at the atleast one additional Ethernet port, an associated at least one Ethernetcable providing low voltage DC power; receiving, at the inverter, acombination of the low voltage DC power from the Ethernet port and thelow voltage DC power from the at least one additional Ethernet port andinverting the combined low voltage DC power into high voltage AC power;providing the high voltage AC power and the electrical connection toprotective earth to devices connected to the AC outlet; utilizing theresidual current device to detect a leak in the high voltage AC powerbeing output via the AC outlet; and shutting down the outputting of thehigh voltage AC power in the event a leak is detected.
 16. The method ofclaim 15, wherein the power distribution unit further includes a networkinterface and a splitter, wherein the Ethernet cable further providesnetworking signals from a network in conjunction with the low voltage DCpower, and wherein the method further comprises provisioning thenetworking signals to a connected device via the network interface. 17.The method of claim 16, wherein the provisioning includes utilizing thesplitter to separate the networking signals from the low voltage DCpower; and utilizing the network interface to provide the separatednetworking signals to the connected device.
 18. The method of claim 17,wherein the network interface is an Ethernet port that receives anEthernet cable having an opposite end connected to the connected device.19. The method of claim 15, wherein the power distribution unit furtherincludes a USB port, and wherein the method further comprises derivingUSB power from the low voltage DC power received; connecting a USBpowered device to the USB port; and powering the USB powered device withthe USB power.
 20. The method of claim 15, wherein the powerdistribution unit further includes a battery, and wherein the methodfurther comprises utilizing the battery to provide DC power to theinverter when the low voltage DC power provided by the Ethernet port isinsufficient to meet demand for power.
 21. The method of claim 15,wherein the Ethernet cable includes four twisted pair of insulatedconductors and a ninth insulated conductor, wherein the ninth insulatedconductor is used to provide the power distribution unit with theconnection to protective earth included in the power source.